This invention relates in general to compression type end fittings and specifically to compression type and fittings for non-metal flexible tubing wherein a tubing reinforcing insert is placed within the tubing to provide support therefor when the compression fitting is tightened about the tubing.
Various types of compression fittings have been employed heretofore for joining non-metal flexible tubing to a valve body fitting wherein a tubing reinforcing insert is employed. Examples thereof are U.S. Pat. Nos. 3,830,531; 3,834,742; 3,903,335; 3,915,479 and 3,685,860. In each of these prior patents, means are provided on the tubing insert for holding it in a removable press fit relationship to the fitting tubing receiving bore or throughbore so that the tubing insert is substantially aligned within the preassembled nut sub-assembly normally employed in compression type fittings. However, it has been found that the tolerances for the internal and external diameters of non-metal flexible tubing, generally of a plastic material, vary sufficiently as to cause difficulty in suitably aligning the tubing, insert and the bores of the nut sub-assembly and fitting so that the tubing can be easily pressed through the nut sub-assembly bore over the insert and into the fitting tubing receiving bore.